- Regioselective Synthesis of Pyrroles from Alkyne-Isocyanide Click Reactions: An Angle Strain-Induced Bond Migration Approach
-
The direct regioselective synthesis of highly functionalized pyrroles with two different electron-withdrawing groups has been developed using an angle strain-induced 1,2-shift of an electron-withdrawing group in 2H-pyrroles. The preferential migration aptitude of an electron-withdrawing group over alkyl and aryl groups is believed to be the result of the orbital overlap between the internal alkene and the electron-withdrawing group. The newly developed regioselective synthesis of pyrroles features a wide substrate scope, simple reaction set-up, and high yields (60–82%), capturing the essence of alkyne-isocyanide “click” reactions. (Figure presented.).
- George, Jimil,Kim, Hun Young,Oh, Kyungsoo
-
supporting information
p. 3714 - 3718
(2016/12/16)
-
- Reaction of functionalized azomethine ylides with acetylenic dipolarophiles: the facile synthesis of functionalized 2H- and 1H-pyrroles
-
The reaction of functionalized azomethine ylides as C-unsubstituted nitrile ylide equivalents with acetylenic dipolarophiles is mentioned. Therein, the initially formed cycloadducts, 2,5-dihydropyrroles, by the reaction of the azomethine ylides with subst
- Kawashima, Keisuke,Hiromoto, Masanori,Hayashi, Kyohei,Kakehi, Akikazu,Shiro, Motoo,Noguchi, Michihiko
-
p. 941 - 944
(2008/02/04)
-
- Unprecedented 1,4-stannatropy: Effective generation of azomethine ylides as nitrile ylide equivalents from N-(stannylmethyl)thioamides
-
Generation and cycloaddition of less- or non-stabilized azomethine ylides, or nitrile ylide equivalents, via unprecedented 1,4-stannatropy of N-(tributylstannylmethyl)thioamides were achieved. The reactions with dipolarophiles, such as electron-deficient alkenes and alkynes, afforded corresponding pyrrolidine and pyrrole derivatives effectively. The Royal Society of Chemistry 2006.
- Komatsu, Mitsuo,Kasano, Yukihiro,Yonemori, Jin-Ichi,Oderaotoshi, Yoji,Minakata, Satoshi
-
p. 526 - 528
(2008/02/05)
-
- Novel generation and cycloaddition of N-silylated azomethine ylides from α-silylimidates and trifluorosilane
-
The Generation of N-silylated azomethine ylides was achieved by the reaction of α-silylimidates and trifluorophenylsilane. The generated azomethine ylides can be regarded as synthetic equivalents of nitrile ylides since they have an alkoxy group which may
- Washizuka, Ken-Ichi,Minakata, Satoshi,Ilhyong, Ryu,Komatsu, Mitsuo
-
p. 12969 - 12976
(2007/10/03)
-
- Novel and convenient routes to substituted pyrroles and imidazoles
-
S-Methyl N-(benzotriazol-1-ylmethyl)thioimidate 6 is obtained by lithiation of the corresponding N-(benzotriazol-1-ylmethyl)thioamide 5 and subsequent reaction with methyl iodide. Derivative 6 undergoes [2+3] cycloaddition reactions with α,β-unsaturated -esters, -ketones and -nitriles, and vinylpyridines which are followed by elimination of benzotriazole and the thioalkoxy group, to give 2,3,4-trisubstituted pyrroles. Lithiation of 6 followed by reactions with imines gives cyclized 4,5-dihydroimidazoles 14 which upon further treatment with ZnBr2 or direct refluxing in toluene yield the 1,2,5-trisubstituted imidazoles 15 in good yields.
- Katritzky, Alan R.,Zhu, Lie,Lang, Hengyuan,Denisko, Olga,Wang, Zuoquan
-
p. 13271 - 13276
(2007/10/02)
-
- Reduction electrochimique de 4H-1,3-thiazines : obtention de 6H-1,3-thiazines et (ou) de pyrroles substitues
-
Controlled potential electroreduction (protic medium, mercury cathode) of substituted 2-ethoxy and 2-phenyl-4H-1,3-thiazines leads to 6H-1,3-thiazines and (or) pyrroles.The nature of the isolated products appears strongly dependent on pH of the medium and
- Abouelfida, Abdesselam,Pradere, Jean Paul,Jubault, Michel,Tallec, Andre
-
-
- A selective electrochemical way to functionalized 6H-1,3-thiazines and/or pyrroles
-
4H-1,3-thiazines, easily prepared from 1-thia-3-azabutadienes, appear electroactive in protic medium. Controlled potential electroreductions of 4H-1,3-thiazines lead either to substituted 6H-1,3-thiazines or to pyrroles according to the nature of the C-4
- Abouelfida,Jubault,Pradere,Roze,Tallec
-
p. 2225 - 2228
(2007/10/02)
-
- Silyl-Substituted Thioimidates as Nitrile Ylide Equivalents
-
Treatment of silyl-substituted thioimidates with silver fluoride in the presence of a trapping agent produces dipolar cycloadducts formally derived from nitrile ylides.The ratio of cycloadducts obtained from the reaction of unsymmetrically substituted dip
- Padwa, Albert,Gasdaska, John R.,Haffmanns, Gunter,Rebello, Hector
-
p. 1027 - 1035
(2007/10/02)
-
- A New and General Route to N-Protonated Azomethine Ylides from N-(Silylmethyl)amidines and -thioamides. Cycloaddition of Synthetic Equivalents of Nitrile Ylides
-
The N- or S-alkylation or -silylation of N-(silylmethyl)amidines or -thioamides and the subsequent desilylation of the silylmethyl group generate N-protonated azomethine ylides bearing a leaving group.These azomethine ylides undergo successful cycloaddition with electron-deficient olefins, acetylenes, and aldehydes.As the leaving group is eliminated under the reaction conditions, these azomethine ylides can be synthetic equivalents of nonstabilized nitrile ylides which are otherwise relatively inaccessible.
- Tsuge, Otohiko,Kanemasa, Shuji,Matsuda, Koyo
-
p. 1997 - 2004
(2007/10/02)
-
- N-PROTONATED AZOMETHINE YLIDES WITH A LEAVING GROUP AS SYNTHETIC EQUIVALENTS FOR NONSTABILIZED NITRILE YLIDES
-
Through alkylation or silylation and then desilylation steps, N-(silylmethyl)amidines generate N-protonated azomethine ylides which cycloadd to olefins, acetylenes, and aldehydes giving 1- or 2-pyrrolines, pyrroles, and 2-oxazolines, respectively, after the elimination of N-substituted anilines.With this sequence, the amidines are useful synthetic equivalents of nonstabilized nitrile ylides.
- Tsuge, Otohiko,Kanemasa, Shuji,Matsuda, Koyo
-
p. 1411 - 1414
(2007/10/02)
-